Formation penetrating tool

ABSTRACT

The present invention relates to a formation penetrating tool submersible into a casing in a well for hydraulically penetrating a formation and having a longitudinal tool axis, comprising a tool housing, a supply hose, slidable in the tool housing, for supplying a high pressurised fluid to a nozzle, and the tool housing having an opening through which the supply hose and the nozzle are led to penetrate the formation, wherein the formation penetrating tool further comprises a pump arranged in the tool housing, the pump being in fluid communication with the supply hose for providing a jet of fluid out of the nozzle for penetrating the formation. Furthermore, the invention relates to a downhole system comprising a formation penetrating tool according to the invention and to a method for hydraulically penetrating a formation.

FIELD OF THE INVENTION

The present invention relates to a formation penetrating tool submersible into a casing in a well for hydraulically penetrating a formation and having a longitudinal tool axis, comprising a tool housing, a supply hose, slidable in the tool housing, for supplying a high pressurised fluid to a nozzle, and the tool housing having an opening through which the supply hose and the nozzle are led to penetrate the formation. Furthermore, the invention relates to a downhole system comprising a formation penetrating tool according to the invention and to a method for hydraulically penetrating a formation.

BACKGROUND ART

When fracturing the formation in order to provide better access to the hydrocarbon reservoir, the maximum reservoir contact is obtained if the fractures are created perpendicularly or radially from the casing or from the bore hole in a well. When fracturing, there is always a risk that the fractures are not made radially from the casing, as the formation cracks at its weakest spots. In some kinds of formation, the fractures tend to be created in parallel to the casing or the bore hole even though the fracturing fluid or perforating charge is directed radially into the formation.

SUMMARY OF THE INVENTION

An object of the present invention is to wholly or partly overcome the above disadvantages and drawbacks of the prior art. More specifically, it is an object to provide a tool enabling a more controlled fracturing process.

The above objects, together with numerous other objects, advantages and features, which will become evident from the below description, are accomplished by a solution in accordance with the present invention by a formation penetrating tool submersible into a casing in a well for hydraulically penetrating a formation and having a longitudinal tool axis, comprising:

-   -   a tool housing,     -   a supply hose slidable in the tool housing for supplying a high         pressurised fluid to a nozzle, and     -   the tool housing having an opening for providing access of the         supply hose and the nozzle to the opening in the casing,         wherein the formation penetrating tool further comprises a pump         in fluid communication with the supply hose for providing a jet         of fluid out of the nozzle for penetrating the formation.

In one aspect, the pump of the downhole penetrating tool may be arranged in the tool housing, the pump being in fluid communication with the supply hose for providing a jet of fluid out of the nozzle for penetrating the formation.

The nozzle may be connected to an end of the hose so that the hose ends in the nozzle.

By having a pump in the tool, fluid from the well can be used as the pressurised fluid ejected through the nozzle for penetrating the formation. Thus, the pressurised fluid needs not be supplied through a long line of tubing extending from surface. This simplifies the tool as it can be submerged down the well by means of a wireline only. Not all rigs are equipped with such tubing and in these cases a special vessel needs to be ordered. Wells can always be intervened by wireline tools as wireline is always present, and thus wireline operations are quicker and less expensive. Having a pump in the tool and not at surface makes it possible to intervene by means of wireline.

In another aspect, the formation penetrating tool may be submersible into a casing in a well by a wireline or by means of tubing, such as coiled tubing or a drill pipe.

In one embodiment, a holding unit may be arranged for providing a predetermined pushing force to the supply hose so that the supply hose and thereby the nozzle may be kept in a predetermined position during penetration.

Thus, the holding unit may be a force generator to prevent the hose from being forced backwards when jetting fluid for penetrating the formation.

In another embodiment, the predetermined pushing force may be at least equal to or larger than a pressure of the high pressurised fluid at the nozzle.

Further, the holding unit may comprise a piston circumferenting the supply hose.

Said piston may be an annular piston.

In one embodiment, the piston may be arranged in a slidable manner in a piston cylinder in the tool.

In another embodiment, several annular pistons may be provided circumferenting the supply hose.

The formation penetrating tool according to the invention may further comprise a casing penetrating unit adapted to provide a hole in a wall of the casing.

Additionally, the piston may be arranged in a piston housing in the tool housing.

In one embodiment, the casing penetrating unit may be arranged in connection with or around the nozzle.

In another embodiment, the nozzle may have an annular opening (orifice) providing a cylindrical jet of fluid.

Also, the casing penetrating unit may be a punch, a drill bit or a charge of a perforating gun.

The nozzle may have a first end connected with the hose and the casing penetrating unit may be a punch provided in a second end of the nozzle opposite the first end.

Moreover, the tool housing may comprise a guiding element for guiding the supply hose out of the opening in the tool housing.

Furthermore, the tool housing may comprise a guiding tube for guiding the supply hose.

Also, the supply hose may be sliding in a fluid channel being in fluid communication with the pump.

In one embodiment, the supply hose may be armoured.

The armouring of the supply hose may be a threadingly arranged in the wall of the hose. The threading may be made of metal, composite, plastic, or similar material.

Further, the supply hose may comprise a plastic core such as a Teflon core, or may be coated with Teflon or other friction-reducing materials.

Moreover, the high pressurised fluid may be well fluid.

In one embodiment, the tool housing may comprise an inlet for the well fluid, the inlet being in fluid communication with the pump.

Having a pump inlet in the tool housing may permit intake of well fluid surrounding the tool.

In another embodiment, a filter or screen may be arranged in connection with the inlet for filtering the well fluid before it enters the pump.

The formation penetrating tool according to the present invention may further comprise a moving device for moving at least the supply hose along the longitudinal tool axis and transverse to the longitudinal tool axis.

Said moving device may be a stroker providing a stroke along the longitudinal tool axis.

In another embodiment, the moving device may be a motor rotating a first part of the tool in relation to a second part of the tool or moving the supply hose in relation to the formation along the longitudinal tool axis.

Further, the first part and second part of the tool may be connected by means of a shaft.

Also, the tool may comprise a first part and a second part and the moving device may move the first part in relation to the second part to move the supply hose along the longitudinal tool axis and transverse to the longitudinal tool axis.

Hereby, a first part of the tool may be moved along the longitudinal tool axis in relation to a second part of the tool moving the supply hose in relation to formation along the longitudinal tool axis. The first part of the tool may comprise the supply hose, the holding unit and the pump, and the second part of the tool may comprise the anchoring section.

The formation penetrating tool may further comprise a cartridge comprising several geophones to be inserted into the bores.

The formation penetrating tool according to the invention may further comprise a fluid reservoir.

Also, the fluid reservoir may contain a supply of fluid.

Furthermore, the fluid may be the pressurised fluid, an acid, a base, or a mixture of substances.

In one embodiment, a fluid control device may be arranged in connection with the fluid reservoir. Hereby, it is obtained that a fluid communication to the fluid reservoir may be opened or closed.

Further, the tool may comprise an anchor section for pressing the penetrating unit against the wall of the casing or anchoring the tool to an inner face of the casing.

In another embodiment, the pump may be powered through a wireline or a battery.

In yet another embodiment, the pump may be a centrifugal pump, a piston pump, or a jet pump.

Also, the tool may comprise a pressure measuring device.

Additionally, the tool may comprise an electronic section.

Further, the tool may comprise a hydraulic motor or an electrical motor for driving the pump.

Moreover, the tool may comprise a position device, such as a casing collar locator, adapted for positioning the tool in the casing in an axial and/or a radial direction of the casing.

Furthermore, the formation penetrating tool may comprise an inlet being in fluid communication with the pump, enabling a well fluid to be used as the high pressurised fluid.

In one embodiment, an additional fluid from a fluid reservoir may be arranged in the formation penetrating tool via the supply hose, and the nozzle may be introduced into the penetrated formation for a subsequent treatment of the penetrated formation.

In another embodiment, the subsequent treatment may be an acid treatment for creating a larger surface area of the penetrated formation.

In yet another embodiment, the subsequent treatment may be an enzyme treatment for cleaning the penetrated formation.

Moreover, the well fluid may be filtered before entering the pump.

The present invention furthermore relates to a downhole system comprising a formation penetrating tool according to the invention and a driving unit, such as a downhole tractor.

Said driving unit may be a self-propelling unit capable of conveying itself and the formation penetrating unit forward in the well.

Also, the driving unit may comprise wheels arranged on wheel arms projectable from the tool housing so that the wheel contacts an inner surface of the well.

Finally, the invention relates to a method for hydraulically penetrating a formation comprising the steps of

-   -   submerging a formation penetrating tool in a casing,     -   providing an opening in a wall of the casing by means of a         casing penetrating unit,     -   supplying a high pressurised fluid to a nozzle via a supply hose         by means of a pump arranged in the formation penetrating tool,     -   positioning the nozzle opposite the opening in the casing, and     -   penetrating the formation by means of a jet of fluid out of the         nozzle providing a formation bore.

The method described above may further comprise at least one of the following steps:

-   -   taking well fluid surrounding the tool in through a inlet in the         tool housing, and     -   pressurising the fluid to a high pressure before supplying the         fluid to the supply hose.

Moreover, the formation penetrating tool may be a wireline tool being submerged into the well via a wireline.

Also, the high pressurised fluid may be well fluid.

Additionally, the method according to the invention may comprise at least one of the following steps:

-   -   performing a subsequent treatment of the formation bore by means         of acid for creating a larger surface area of the formation         bore,     -   injecting a fluid comprising enzymes into the formation bore,     -   fracturing the formation by injecting high pressurised fluid         into the formation bore, or     -   perforating the formation by exploding a charge in connection         with the formation bore.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments and in which

FIG. 1 shows a formation penetrating tool in a casing,

FIG. 2 shows a cross-sectional view of the formation penetrating tool,

FIG. 3 shows one embodiment of a holding unit,

FIG. 4A shows a cross-sectional view of another embodiment of the formation penetrating tool,

FIG. 4B shows a cross-sectional view of yet another embodiment of the formation penetrating tool,

FIG. 5 shows yet another embodiment of the formation penetrating tool,

FIG. 6 shows a front view of a nozzle,

FIG. 7 shows another formation penetrating tool in a first position in the casing,

FIG. 8 shows the formation penetrating tool of FIG. 7 in a second position,

FIG. 9 shows the formation penetrating tool of FIG. 7 in a third position, and

FIGS. 10A-D show cross-sections of different bores in the formation made by the formation penetrating tool.

All the figures are highly schematic and not necessarily to scale, and they show only those parts which are necessary in order to elucidate the invention, other parts being omitted or merely suggested.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a formation penetrating tool 1 submerged in a casing 2 in a well 3. In order to penetrate the formation, the tool 1 has a tool housing 4 in which a casing penetrating unit 5 adapted to provide a hole 6 in a wall 7 of the casing 2 is arranged. Subsequently, a nozzle 10 is arranged in an end of a supply hose 8, slidable within the tool housing 4. The supply hose 8 supplies a high pressurised fluid 9 to the nozzle 10 which is jetted as a jet stream out through the hole 6 in order to penetrate the formation, thereby providing a formation micro-bore substantially radially from the formation penetrating tool 1. The formation penetrating tool 1 comprises a pump 12 which is in fluid communication with the supply hose 8 for providing a jet 13 of fluid out of the nozzle 10 to penetrate the formation creating the micro-bore or formation bore 32. The formation penetrating tool 1 may penetrate the casing 2 by means of the high pressurised fluid jetted through the nozzle 10, and thus the tool may function without using the casing penetrating unit 5. However, in the following the function is explained including the use of a casing penetrating unit 5.

When fracturing the formation to provide better access to the hydrocarbon reservoir, there is a risk that the fractures are not made radially from the casing 2. Thus, by providing a micro-bore by means of the formation penetrating tool 1, the fracturing process can be controlled better since a micro-bore acts as a notch. The fracturing process may be performed by means of high pressurised fluid pumped down into the casing 2 or by a perforating gun. In addition, the micro-bore may be used before performing an acidifying process.

The tool housing 4 has an opening 11 for providing access of the supply hose 8 and the nozzle 10 to an opening in the casing 2. To penetrate the formation, the supply hose 8 is led out through the opening 11, and fluid 9 is jetted out through the nozzle 10. The high pressurised fluid jetted into the formation is pressurised in the pump 12. The pump 12 pumps well fluid in through an inlet 21 and a filter 22 arranged in the inlet 21 and pumps the well fluid via the supply hose 8 out through the nozzle 10. By using well fluid to penetrate the formation creating the micro-bore 32, the reservoir is not further contaminated. In addition, the power needed for the jetting process is less than if the pump was arranged at the top of the well and the fluid was pumped down to the supply hose 8 through a drill pipe or coiled tubing. The pump 12 is arranged in the tool and is driven by an electrical motor 29 which is powered by a wireline through an electronic section 28. The formation penetrating tool 1 is thus a wireline tool. The formation penetrating tool 1 is submerged into the well or casing only through such wireline, e.g. with another form of power supply line such as an optical fiber, and not through tubing such as coiled tubing, drill pipe or similar piping.

The formation penetrating tool 1 comprises an anchoring section 25 to force the casing penetrating unit 5 against the casing wall. The tool may have several anchoring sections 25.

When the jet of fluid 9 hits the formation, the formation crunches but the force of the jet will also force the supply hose backwards. Therefore, the tool comprises a holding unit 14 which holds the supply hose 8 and thus the nozzle 10 close to the formation. The holding unit 14 provides a predetermined pushing force to the supply hose so that the supply hose and thereby the nozzle may be kept in a predetermined position during penetration so that the jet 13 does not lose its jetting power before reaching the formation. The predetermined pushing force is substantially equal to or up to 5% smaller than the pressure of the high pressurised fluid at the nozzle.

As can be seen in FIG. 2, the holding unit 14 comprises a piston 15 arranged around the supply hose 8 so that the hose penetrates the piston at its centre, the piston thus being an annular piston. The piston 15 is slidably arranged in a piston housing 16 in the tool housing 4 so that the hose can extend into the formation bore as the formation bore is created. The pressurised fluid 9 from the pump 12 is pumped into a fluid channel 20 which in FIG. 2 functions as the piston housing 16. The fluid acts upon the piston, forcing the hose out into the formation bore as it is created by the jet 13. In FIG. 2, the holding unit 14 is the piston sliding in the piston housing 16. The supply hose 8 is guided in the formation penetrating tool 1 by a guiding tube 19 and a guiding element 18 in order to slide without creating substantial friction.

In FIG. 2, the casing penetrating device is casing penetrating unit 5 arranged around the nozzle 10, and the guiding element 18 is part of the casing penetrating unit 5. In this embodiment, the nozzle has a first end 101 connected with the supply hose and a second end 102 opposite the first end being connected with the casing penetrating unit. In another embodiment, the casing penetrating unit 5 is arranged in the second part of the formation penetrating tool 1 and is slided away from opening when the opening has been made so that the nozzle and the supply hose can enter the formation.

The casing penetrating unit is a punch 64 in FIG. 2, but may also be a drill bit or a charge 33 of a perforating gun forming part of the tool as shown in FIG. 4A. The punch shown in FIG. 2 is forced outward towards the casing in order to penetrate the casing wall, creating a hole 6 in the wall by means of a sliding element 42 slidable arranged in a space 43 in the tool housing 4. The sliding element 42 comprises an inclined surface 44, and when the sliding element 42 is forced away from the pump 12 by means of pressurised fluid in a fluid channel 45 indicated by a dotted line, the punch is forced out of the opening in the tool housing 4 and punches a hole in the casing wall.

In FIG. 4A, the charge 33 is activated by a contact 34 arranged in the piston housing and when the piston slides past the contact, the side of the piston presses on the contact and the charge is initiated by the wiring 35, and the charge explodes, creating an opening in the casing wall.

The supply hose 8 is armoured by a threading, e.g. made of metal, embedded in the wall of the hose so that the hose is self-supporting and will not kink when bending and that the holding unit can exert pressure from one end or along the hose in order to provide a holding pressure in the other end of the hose countering the pressure from the formation when the jet hits the formation. The supply hose may also comprise a plastic core, such as a Teflon core, or be coated with Teflon or other friction-reducing materials in order to supply the pressurised fluid 9 without losing too much pressure.

In FIG. 3, the holding unit 14 comprises a first 40 and a second 41 piston arranged around the supply hose 8 at a distance from each other, creating a chamber 37 there between. The first piston is arranged closest to the nozzle. The holding unit 14 also comprises a fluid channel 38 in fluid communication with the pump 12 or an additional pump providing a pressure on the first piston 40, forcing the hose outward towards the formation and thus holds the nozzle sufficiently close to the formation in order to crunch the formation by means of the jet of pressurised fluid 9. The second piston and the aforementioned piston 15 may be the same piston.

As shown in FIG. 5, the formation penetrating tool 1 may comprise a fluid reservoir 23 containing the fluid 9 if the pump does not take in well fluid or the reservoir 23 may contain an additional fluid. The fluid may be any kind of fluid, such as water, an acid, a base, a mixture of substances. The additional fluid from the fluid reservoir may also be introduced into the penetrated formation for a subsequent treatment of the penetrated formation, so that a second run in order to fracture the formation using the micro-bore 32 is no longer needed.

The formation penetrating tool 1 also comprises a fluid control device 24 arranged in connection with the fluid reservoir 23 so that a fluid communication between the pump 12 and the fluid reservoir may be open or closed. By having the fluid control device 24, the additional fluid in the fluid reservoir can be mixed with the well fluid pumped in by means of the pump, and thus the fluid control device 24 can control the amount of fluid from the reservoir which is mixed with the well fluid.

In FIG. 6, the nozzle has an annular orifice providing a cylindrical jet of fluid. In this way, the fluid creates an annular micro-bore around a formation centre part which may be brought up with the tool with a view to analysing the formation so that an optimal fracturing process can be initiated.

The formation penetrating tool 1 is powered by wireline 26 or a battery arranged inside the tool. When the formation penetrating tool 1 comprises a battery, the line 26 can be any line strong enough to pull the tool out of the well after the penetrating operation.

In FIG. 5, the formation penetrating tool 1 comprises a pressure measuring device 27 for measuring the pressure of the fluid 9 supplied through the supply hose. The formation penetrating tool 1 also comprises a position device 30, such as a casing collar locator, adapted to position the formation penetrating tool 1 in the casing in an axial and/or a radial direction of the casing 2. Furthermore, the position is used for finding the formation micro-bore in the following fracturing process.

The pump may be a centrifugal pump, a piston pump or a jet pump.

FIG. 5 shows a downhole system 100. The downhole system comprises the formation penetrating tool 1 and a driving unit 31, such as a downhole tractor. The driving unit is mainly used to drive and convey the formation penetrating tool 1 and itself forward in a horizontal part of the well but may also be used as an anchoring section or a positioning device. The driving unit comprises wheels 63 arranged on wheel arms 61 projectable from the tool housing in order for the wheels to contact the inner surface of the well, casing or borehole.

In FIG. 7, the formation penetrating tool 1 comprises a moving device 50 moving a first part 51 of the tool in relation to a second part 52 of the tool in order to move the supply hose 8 along a longitudinal tool axis or rotating the supply hose 8 in a direction transverse to the longitudinal tool axis. The first part and the second part are connected by means of a shaft 53. The moving device 50 may comprise a stroker providing a stroke along the longitudinal tool axis so that the first part 51 is moved away from or closer to the second tool part 52. The moving device 50 may also comprise a motor for rotation of the first part of the tool in relation to the second part of the tool or for the first part of the tool in relation to the second part of the tool along the longitudinal tool axis and thereby moving the supply hose 8 in relation to the formation along the longitudinal tool axis. The orientation could also be performed by means of a swivel or a relative bearing measurement.

By having a moving device 50, the first part 51 of the tool can be moved along the longitudinal tool axis or transverse to the tool axis in relation to a second part 52 of the tool moving the supply hose in relation to the formation or the casing along the longitudinal tool axis or rotating the supply hose along a direction transverse to the longitudinal tool axis. By being able to move the supply hose 8, the hole 6 in the casing 2 or the bore resulting from the high pressurised fluid 9 being jetted into in the formation can be made larger than just by penetrating the casing or the formation once. Penetrating the formation once by jetting fluid 9 through the supply hose 8 out through the nozzle 10 results in a hole 6 in the casing or a bore in the formation having the cross-section as shown in FIG. 10A. When moving the supply hose 8 by means of the moving device 50, the hole 6 in the casing or the bore in the formation is enlarged to have the cross-section as illustrated in FIGS. 10B-D.

In a first position as shown in FIG. 7, the formation penetrating tool 1 penetrates the casing 2 or the formation making a hole or formation bore 32 transverse to the tool axis. In FIG. 8, the moving device 50 has moved the first part 51 of the tool to a second position in which the first tool part 51 is moved further away from the second tool part 52. In this second position, the formation penetrating tool 1 penetrates the casing 2 or the formation in a displaced position in relation to the first hole or formation bore and thus extends the hole or the formation bore, making the hole or bore larger along the longitudinal tool axis. In FIG. 9, the formation penetrating tool 1 is shown in its third position in which the moving device 50 has moved the first part closer to the second part compared to the first and second positions. In this third position, the fluid 9 jetted from formation penetrating tool 1 penetrates the casing 2 or the formation, extending the hole of the bore even further and resulting in a hole or bore having a cross-section as shown in FIG. 10D.

In FIG. 10B, the supply hose 8 has been rotated along a direction transverse to the longitudinal tool axis making a longitudinal hole in the casing 2 or a longitudinal bore in the formation in a plane transverse to the longitudinal tool axis. In FIG. 10C, the supply hose 8 has been both rotated and moved along the longitudinal tool axis. In FIG. 10D, the longitudinal bore extends along the longitudinal tool axis.

By making longitudinal micro-bores or holes in the formation, the subsequent fracturing process injecting fracturing fluid into the formation in the bore or hole can be directed in the optimal direction, thus orienting the micro well bores to maximise the effectiveness of the fractures. Fractures tend to orient themselves in the maximum stress direction, and by orienting the micro holes in the maximum stress direction, most of the fracture energy will be used to propagate the fracture.

The first part 51 of the formation penetrating tool 1 comprises the supply hose 8, the holding unit 14 and the pump 12, and the second part 52 of the tool 1 comprises the anchoring section 25. The moving device 50 may be comprised in the first tool part 51 and attached to the second tool part 52 by means of the shaft 53 or be comprised in the second tool part 52 and connected to the first tool part 51.

After having made a micro-bore or bore in the formation, the tool may insert a geophone in the bore in order to conduct e.g. seismic measurements. The formation penetrating tool 1 may comprise a cartridge comprising several geophones to be inserted into the bores. In this way, the formation penetrating tool 1 may be used to upgrade or improve a well to have a seismic system in order to conduct measurements of the presence of hydrocarbons in the formation.

By fluid or well fluid is meant any kind of fluid that may be present in oil or gas wells downhole, such as natural gas, oil, oil mud, crude oil, water, etc. By gas is meant any kind of gas composition present in a well, completion, or open hole, and by oil is meant any kind of oil composition, such as crude oil, an oil-containing fluid, etc. Gas, oil, and water fluids may thus all comprise other elements or substances than gas, oil, and/or water, respectively.

By a casing is meant any kind of pipe, tubing, tubular, liner, string etc. used downhole in relation to oil or natural gas production.

Although the invention has been described in the above in connection with preferred embodiments of the invention, it will be evident for a person skilled in the art that several modifications are conceivable without departing from the invention as defined by the following claims. 

1.-23. (canceled)
 24. A formation penetrating tool (1) submersible into a casing (2) in a well (3) for hydraulically penetrating a formation and having a longitudinal tool axis, comprising: a tool housing (4), a supply hose (8), slidable in the tool housing, for supplying a high pressurised fluid (9) to a nozzle (10), and the tool housing having an opening (11) through which the supply hose and the nozzle are led to penetrate the formation, wherein the formation penetrating tool further comprises a pump (12) arranged in the tool housing, the pump being in fluid communication with the supply hose for providing a jet (13) of fluid out of the nozzle for penetrating the formation.
 25. A formation penetrating tool according to claim 24, wherein a holding unit (14) is arranged for providing a predetermined pushing force to the supply hose.
 26. A formation penetrating tool according to claim 25, wherein the holding unit comprises a piston (15) circumferenting the supply hose.
 27. A formation penetrating tool according to claim 26, wherein the piston is arranged in a slidable manner in a piston cylinder in the tool.
 28. A formation penetrating tool according to claim 26, wherein several annular pistons are provided circumferenting the supply hose.
 29. A formation penetrating tool according to claim 24, further comprising a casing penetrating unit (5) adapted to provide a hole (6) in a wall (7) of the casing.
 30. A formation penetrating tool according to claim 29, wherein the casing penetrating unit is arranged in connection with or around the nozzle.
 31. A formation penetrating tool according to claim 30, wherein the nozzle has a first end (101) connected with the hose and the casing penetrating unit is a punch provided in a second end (102) of the nozzle opposite the first end.
 32. A formation penetrating tool according to claim 24, wherein the supply hose is sliding in a fluid channel (20) being in fluid communication with the pump.
 33. A formation penetrating tool according to claim 24, wherein the tool housing comprises an inlet (21) for the well fluid, the inlet being in fluid communication with the pump.
 34. A formation penetrating tool according to claim 24, further comprising a moving device (50) for moving at least the supply hose along the longitudinal tool axis and transverse to the longitudinal tool axis.
 35. A formation penetrating tool according to claim 24, wherein a fluid control device (24) is arranged in connection with the fluid reservoir.
 36. A downhole system comprising a formation penetrating tool according to claim 24 and a driving unit (31), such as a downhole tractor.
 37. A downhole system according to claim 36, wherein the driving unit is a self-propelling unit capable of conveying itself and the formation penetrating unit forward in the well.
 38. A downhole system according to claim 36, wherein the driving unit comprises wheels arranged (60) on wheel arms (61) projectable from the tool housing so that the wheel contacts an inner surface of the well.
 39. A method for hydraulically penetrating a formation comprising the steps of submerging a formation penetrating tool in a casing, providing an opening in a wall of the casing by means of a casing penetrating unit, supplying a high pressurised fluid to a nozzle via a supply hose by means of a pump arranged in the formation penetrating tool, positioning the nozzle opposite the opening in the casing, and penetrating the formation by means of a jet of fluid out of the nozzle, providing a formation bore.
 40. A method according to claim 39, further comprising at least one of the following steps: taking well fluid surrounding the tool in through a inlet in the tool housing, and pressurising the fluid to a high pressure before supplying the fluid to the supply hose.
 41. A method according to claim 39, wherein the formation penetrating tool is a wireline tool being submerged into the well via a wireline.
 42. A method according to claim 39, wherein the high pressurised fluid is well fluid.
 43. A method according to claim 39, further comprising at least one of the following steps: performing a subsequent treatment of the formation bore by means of acid for creating a larger surface area of the formation bore, injecting a fluid comprising enzymes into the formation bore, fracturing the formation by injecting high pressurised fluid into the formation bore, or perforating the formation by exploding a charge in connection with the formation bore. 